1. Field of the Invention
The present invention relates generally to an image-forming apparatus and a power-saving mode control method thereof. More particularly, the present invention pertains to an image-forming apparatus and a power-saving control method for reducing a printing time by reducing a warm-up time when a power-saving mode powers off as well as preventing motors from being unnecessarily driven and a fuser from being heated.
2. Description of the Related Art
Image-forming devices print images onto a recording medium such as paper corresponding to original image data that was input. Examples of image-forming devices include printers, photocopiers, and facsimile machines. In general, image-forming apparatus have a power-saving mode to reduce power consumption when the image-forming apparatus is not used.
A description will now be made on the operation of an image-forming apparatus having a conventional power-saving mode function.
FIG. 1 is a flowchart illustrating the operation of an image-forming apparatus having a conventional power-saving mode function. Referring to FIG. 1, if a user requests a power-saving mode or if a standby state lasts for a certain time, the image-forming apparatus goes into the power-saving mode at step S11.
In the power-saving mode, the image-forming apparatus determines whether a request is made to turn off the power-saving mode at step S12.
The power-saving mode is turned off when a print command is received from a host or when sensors related to the turn-off of the power-saving mode operate. The sensors related to the turn-off of the power-saving mode include a sensor for detecting whether the printer cover is opened, a sensor for detecting whether cassettes exist, a sensor for detecting whether paper exists in the cassette, and a sensor for detecting manually loaded paper.
If there is the request to enter the power-saving mode, the image-forming apparatus enters the power-saving mode. If the image-forming apparatus goes from the power-saving mode, the image-forming apparatus performs certain warm-up operations for a period, and enters a standby mode at step S13. If the power-saving mode is turned off due to the print command, the apparatus goes into the print mode when entering the standby mode.
Image-forming devices having the above conventional power-saving mode function perform the warm-up operation when receiving a print command after entering the power-saving mode, or when turning off the power-saving mode due to operation of the cover detection sensor, the paper detection sensor, or the like. Thus, the devices takes a certain time period to warm up when the power-saving mode is turned off. However, the warm up time may be unnecessary depending on the circumstances.
For example, the apparatus may start printing after the warm-up operation even when receiving a print command just as it was entering the power-saving mode. This results in a delay in printing based on the unnecessary warm-up period.
Furthermore, a heated fusion roller results in unnecessary power consumption during warm-up. The driving of motors during the warm-up activates the photosensitive drum together with most of other rollers such as a transfer roller, a developing roller, and a charging roller so that the life span of the rollers may be shortened.